What is a Witness Tree?

If it is NOT a hanging tree, and DOES NOT have any religious significance… would you believe… It is an ancient oak tree, that towers over our 100-acre estate and used as a a surveyor’s landmark in 1854, bearing “witness” to the northwest corner of the Donation Land Claim No. 51 granted to early pioneers, Claiborne C. Walker and his wife, who arrived in a covered wagon via the Oregon Trail. July 8th, 2004 celebrated the 150th Anniversary of the marking of this Historic Tree.